Focusing mechanism



I June 23, 1931. G, H, CUSHING 1,811,715

FOCUSING MECHANISM Filed Feb. 16, 1929 2 Sheets-Sheet l Snvcntor June 23, 1931 G. H. cusHlNG 1,811,715

FOCUS ING MECHANI SM Filed Feb. 16. 1929 2 sheets-sheer 2 :inventor Patented June 23, 1931 UNITED'STA'I'ES PATENT OFFICE GEORGE II. CUSI-IING, OF IVASHING'I'ON, DISTRICT OF COLUMBIA, ASSIGNOB TO CUSH- Y ING LAMP INCORPORATED, OF WASHINGTON, DISTRICT 0F COLUMBIA, A COR- roaarron or nnnfmrnmaV Focusrite MECHANIS'M Application `filed February 16, 1929. Serial No. 340,570.

This invention relates generally to illumination and more particularly has reference to a'mechanism for adjusting the position of a light source relative to the reflector of a projectinglamp, and to means for retaining the light sourcef in adjusted positions.

Projecting lamps that are scientifically'constructed aredesigned upon a predetermined' of a projecting lamp designed 'for a particular relation between the filament and the reflector. j

Anobject of this inventionv is to devise a mechanism for moving a light source relative to a reflector of a projecting lamp to secure a desired relation between the light source4 and a reflector.

Another object of this invention is to provide a mechanism by means of which a light source may be adjusted to various positions relative to a reiiector and which is provided with a means for locking the light-source in any adjusted position.

Another object of this ,invention is to provide a mechanism for mounting'a light source within a projecting lamp in such a manner that the light source may be finally adjusted to various positions.

Another object of this invention is to devise a mechanism for mounting a light source in a projecting vlamp in such a manner that the light source may be adjusted to various posi-y tions without being rotated.

Still another object of this invention is to devise a mechanism for supporting a light source within a projecting lamp in such a manner that it may be accurately adjusted to various positions relative to a reflecting surface, and which is capable of being easily'attached to the light supporting means ofa projecting lamp. j Y

With these and other objects in'view which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter setforth and claimed, with the understanding that the severalnecesf sary elements comprising my invention may be varied in construction, proportions, and arrangement without departing from the spirit and scope of the appended claims.A

In order to make my invention more clearly understood, I have shown in the accompanying drawings means for carrying the same into practical effect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation have been made the subject of illustration.

In the drawings:

Figure l is a side view of the mechanism for adjustably supporting an electric 'lamp v relative to a reiiecting surface.

Figure 2 is a view showing the lamp carrying mechanism mounted in operative position within a projecting lamp.

Figure 3 is a view similar to Figure 1 with parts ofthe mechanism removed in order to show the details of lconstruction of the slotted supporting member.

Figure 4c is a sectional view of the nut adapted to cooperate with the slotted portion of the supporting member shown in Figure 3.

Figure 5 is a sectional view of the nut adapted to be threaded onto the supporting member shown in Figure 3 to securely connect the supporting portion to the housing of the projecting lamp.

Figure 6 is a view showing a lamp socket threadedly mounted within the bushing which cooperates with the supporting member to move the lamp socket to various positions.

Figure 7 is a sectional View through the supporting member with all other parts removed.

Figure 9 isa view of the threadedlamp socket Figure 10 is an cud view of the supporting member shown in Figure 7 looking at the tapered end.

Figure 11 is an end view of the supporting member taken from the other end thereof.

Figure l2 is a sectional view of the device shown in Figure 1 showing the details of construction.

Figure 13 is a` partial sectional view ot' the focusing device showingl the details of construction of the spring-operated shoe.

`Figure 11 is a view showing the shoe and its supporting member.

Ratei-ring to the drawings, in Figure 1 my device is shown mounted on a. wall or support 1 represented by the dotted line construction. V his wall or support 1 niay constitute a portion of any structure to which the device supporting the adjustable lightI source may he applied. In some instances, however, it will be desirable to mount the mechanism supporting and adjusting a light source on the housing ot a projecting lamp so that the light source may be adjusted axially of a retlector or" the parabolic or other similar type.

is shown in Figure 2 the tubular structure for supporting the adjustable light source l is secured to the support 3 in the projecting limp in such a manner that the light source 2 and its protecting bulb 4i may be moved axially of the structure 5. v

The device which is adapted to be secured to a lamp housing or other supporting meinber, tor r-zdjustably holding the light source Q and its protecting bulb Ll includes among other parteI a combined support and clutch 6. Referring more particularly to Figures 1, 3, 7 and 12, it will be seen that this member 6 comprises a tubular structure having a body portion 7 troni one end of which entends an annularly projecting liange S. Screw threads 9 are provided on the body portion 7 onto which is threaded a nut 10 which is shown in detail in Figm'e In mounting the member 6 on a supporting Vall, an aperture is provided in the wall into which the tubular member 6 is inserted. llhen in place, the iiange 6 engages on-V side oiE the wall and the nut 1() is threaded onto the screw threadsQ in such a manner that it engages the wall ano. securely holes it between the nut 16 and the iiange 3.

Extending 'trom the body portion of the tubular member 6 is a reduced portion 11, the end ot which tapers to a smaller diameter and thereby forming a tapered surface 1Q, the purpose ot which will appear hereinafter. The reduced portion 11, as shown clearly in F i gures 3, 7 and 1() is provided with a plurality ot slots 13 which impart resiliency to it. A. plurality ot screw threads 14 are provided within the reduced port-ion 11 of the supporting member, into which enthreaded an eX- teriorly and interiorly threaded bushing or sleeve 15. 11s shown in the drawings the exterior threads 16 are of a pitch and hand corresponding` to the pitch and hand of the threads 1-1, whereas the interior threads 17 are ot a pitch greater than the threads 16 and are of an opposite hand.

For purposes of illustration, the threads 16 have been shown as right handed, while threads 17 have been shown as lett handed. I wish itto be understood, however, that either set of threads may be of either hand and also the pitch of either set ot threads 16 or 17 may be greater than the other or equal to each other, depending upon the particular results desired. In order to rotate the bushing 15 one portion thereof is knurled, as at 18, or otherwise constructed, so that it can be gripped with ones fingers.

Slidably mounted in the tubular member 6 is a sleeve 19 which serves as a socket for receiving the base 2O ot the bulb 4. This member is provided with bayonet slots 21 at each end, one set of which is adapted to receive pins projecting from the base of an electric bulb and the other set of which is provided for the reception of pins projecting from a connecting plug 22. As shown in Figure 12, a member 23, formed of insulating material and having resiliently mounted current conductors E24 embedded therein, is positioned in the sleeve or socket 19 and serves to conduct current from plug 22 to the light source. It is, of course, obvious that any other construction suitable for connecting a light source to a source of electric energy may be employed.

Sleeve 19 is provided with exterior threads 25 which are of the same pitch and hand as threads 17 Vof bushing 15. As shown in the drawings, threads V25 are left handed, but I wish it to be understood that they may be right handed provided the other threads are changed accordingly to produce the Vdesired result.

lll/lith theV bushing 15 mounted in the tubular member 6 and the socket forming sleeve 19, enthreaded within the bushing 15, it will be clear that if the member 6 and the sleeve 19 are held against rotation and the bushing 15 rotated, the sleeve 19 will, by reason of the diliierential thread construction move relatively to the tubular member 6. Thus with the member 6 secured to a iixed support, such as shown in Figure 2, a bulb carried by the sleeve 19 will be moved axially ot the reflector upon rotation ot the bushing 15.

In 'order to prevent the sleeve or socket from rotating upon rotation. of the bushing 15, the sleeve ,is provided with a slot 26, .termed inthe walls thereof between the bayonet slots 21. Projecting into the slot 26 is a shoe 27 carried by a spring pressed plunger 28 having a diameter larger than the width ot the slot 26, the purpose of which will appear hereinafter. The plunger is mounted in an aper turc provided .in the flange 8, together with a suitable spring 29 and a plug- 8O 'for holding the spring in en gagemeut with the plunger.

As betorementioned, and as clearly Ashown in Figure 13, the plunger is ot a diameter greater than the width of slot 26 so that it will not be forced out of place when the base of a bulb is removed from the socket 19. It will be noted that a portion of the plunger is reduced in size so that the shoe will project slightly into the socket 19. This construction permits the action of the spring 29 to be transmitted through shoe 27 to the side of the base of a bulb mounted in the socket, so thatthe bulb will be frictionally held against accidental displacement. To prevent the shoe interfering with the insertion of a lamp in the socket a portion of the shoe is rounded olf as shown at 31 in Figure, 111.V vIf desired the other end of the shoe 27 may be rounded similar to the portion 31. While it is desirable to utilize the shoe construction just described, for preventing rotation of the sleeve 19 in the member 6, other constructions may be used such as an ordinary projectingv lug mounted on member 6.

The slot construction just,l described also serves to prevent the light source from rotating. It is important that the light source does not rotate as the efficiency of the projecting device depends to a certain extent on the position of the filament of the light source. When the projecting structure is designed for one position of the filament, it is essential that the latter be maintained in that position.

Once an adjustment is made on the device just described it may be maintained by a novel clutch arrangement. As previously7 described, the reduced portion 11 of member 6 is provided with slots 13 to divide the reduced portion into a plurality of jaws. The esternal surface of this reduced portion is also provided with a tapered surface 12. A suit able clutch clamping nut 32, shown in detail in Figure 4, is provided with internal threads 33 adapted to engage with threads 9 on tubular member 6 and with a tapered portion 311 adapted to engage with the tapered surface 12. As the clamping nut 32y is threaded onto the threads 9 the tapered portion 341 engages with the tapered surface 12 and causes the jaws formed from the reduced surface of the Y member 6 to tightly clamp the externally threaded portion of the bushing 15. When the clamping nut 32 is in operative position, the bushing 15 will be held against rotation and the sleeve 19 will be securely held in an adjusted position. The type of locking de vice just described has a tendency to automatically lock itself. For instance, when subj ected to vibrations instead of becoming loo-se, the nut 32, due to the taper construction, becomes more secure on the member on which it is mounted.

It will be noted from the drawings that the end of member 6 adjacent flange 8 is provided with a lip 35 which may serve as a support for a reflector with which the device is associated.

In some instances it will be desirable to have the bulb of such a size that it may be drawn wit-hin the tubular member 6. This ly shown in Figure 12. The structure is then secured to a supporting wall or to the housing of aprojection lamp by means of the nut 10 and the annular Hangs 8. After a bulb has been inserted in a socket provided by sleeve 19', the sleeve may be moved as desired, by rotating the bushing 15 in the proper direction. It will be appreciated that by constructing the threads 16 and 17 of opposite hand and rotating the bushing 15 through one revolution that the bushing` will move into the member 6 a distance equal to the pitch of threads 16 and that the sleeve 19 will move through bushing 15a distance equal to the pitch Vof threads 17. Thus upon one revolution of the bushing 15 the sleeve 19 will move relatively to the member 6 a distance equal to the sum of the pitches of threads 16 and 17.

IVhen the sleeve 19 carrying the bulb is adjusted to the desired position, the clamping nut 32 may be tightened so that the jaws of the clutch, form-ed by slotting the reduced portion 11 of member 6, will tightly engage the external threaded surface of bushing 15 and prevent any rotation thereof.

It will be observed from the foregoing description that this invention provides a construction by means of which the light source may be moved to any desired position axially of a reflector so that the best results can be obtained. It will also be appreciated that my device provides a means for locking the light source after it is once adjusted so that it will not be accidentally displaced.

While I have shown and'V described the preferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise details of construction herein set'forth, by way of illustration, as it is apparent that may changes and variationsmay be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims. y

I claim:

1.1 A device for adjusting` the position of a filament of an electric light bulb relatively to a reflecting surface, comprising a tubular member mounted in fixed relation to a rei'iecting surface, a. sleeve adapted to receive the base of an electric light bulb slidably mounted in said member, an internally and externally threaded bushing Apositioned between said sleeve and member, the external threads being` ot one hand and engagino' with threads in said member', the internal threads being of an' ther hand and e gn gine` with threads on sleeve, stid bushinb` upon rotation being adapted to more the sleeve relatively to said men'iber, and tightening means carried by said member tor lockingthe sleeve in adjusted positions.

il. fr tocas-,ingr` mechanism Yto a projecting lamp, comprisingf a tubular member having a bodyv portion and a reduced portion, an annular dan extending` from the body portion of the tubular member, a nut adapted to be f threaded on said portion to cooperate with said llange Jfor seeming said member to a supporting' wall, the reduced portion ot said member beingA slotted to provide a plurality ot' jaws, supporting means for a light source slidably mounted in said tubular Anember, means for adjusting the position of' said supporting means, a` clamping nut threaded on said tubular member and adapted to torce said jaws into irictional engagement with said supporting,` means to prevent movement thereof.

f5. device ol the character described comprising a lamp socket, means threaded'ly engaging' said socket tor moving it axially, said socke-U having` a slot cut axially adjacent one end and means adapted to cooperate with said slot tor preventing rotation ot' said socket, said last mentioned means comprising a springpressed shoe adapted to frictionally engage with the of a lamp mounted in said socket.

4. ln combination with a projecting reflector a device for holding a lamp at the toons ot said reflector comprisinga supporting member, a lamp socket han/ing external threads and means for moving said socket relative to said supporting member, said member having an annular projection internally threaded, bushingl externally threaded and mounted within said projection, said busl 'ng' also beine' internally threaded and adopted to cooierate with the threads ot said socket, said threads being so constructed that when said bushingl is rotated relatively to said member said socket will move axially relatively to said bushing and said member. .5. An adjustable lamp holder comprising an annular supportingl member internally threaded, a lamp socket having,` external threads, a bushing externally threaded and positioned in said member, said bushing also being' internally threaded to receive the externally threaded lamp socket, the threads between said member and said bushing),` being oione hand and the threads between said bushing and said socket being of the other hand, and the pitch ot the threads between said socket and said'bushing being greater than the pitch of the threads between said bushing and said member.

6. Ain adjustable lamp holder comprising an. annular supporting member internally threaded, a lamp socket having; external threads, a bushing externally threaded and positioned in said member, said bushinpr also being,` internally threadel to receive the ef;- ternally threaded lamp socket, the pitch oi" the threads between said bushing' a n supporting member being less than the pitch ot the threads between said bushing and said socket.

7. An adjustable lamp holder comprising` an annular supporting member internally threaded, a lamp socket having external threads, a bushingr externally threaded and positioned in said member, said bushingv also being internally threaded to receive the externally threaded lamp socket, the threads between said member and said bushing4 being ot one hand and the threads between said bushing and said socket being of the other hand.

ln testimony whereof l athx mv signature.

-GEQRGE H. CSHING.

llt) 

